Shooting Raw will provide more latitude for adjustments in pp.
You can gain a full stop by getting closer and setting the zoom ring on your 55-200mm to 55mm (f/4) which will help a little.
You list a Nikkor 50mm lens in your profile. Which one do you have?
Assuming it is the 50mm f/1.4G AF-S you can gain a full 4 stops (f/5.6 > f/1.4) which will provide 16 times more light through the lens which should provide enough headroom to not only provide a correct exposure but to increase the shutter speed as well allowing you to better freeze your subjects movement. Assuming your images are under exposed by 2 stops (1/60th sec., f/5.6, ISO 800) at f/1.4 your settings would be: 1/250th sec., f/1.4, ISO 800 where 2 stops are applied to correcting the exposure and the additional 2 stops are applied to increasing the shutter speed to better freeze the subjects motion. You will loose DOF (Depth of Field) but gain exposure and shutter speed.
You list the Vivitar DF400 MZ Speedlight in your profile. Are you sure it is working correctly? The Exif data indicates that the flash fired in TTL mode though the images do not look like flash made any contribution to the exposure what-so-ever. The DF400 MZ is a reasonably powerful as it has the same guide number at an SB-600. Moving closer would also provide more light if you use the Speedlight. Shooting closer and using a wider focal length should also reduce the "red-eye" effect induced by shooting at 165mm.
If you can, go to a dress rehearsal and do some experimenting with exposure. Try different things and see what works best for you. Good Luck and Enjoy your Nikons!